Long-term Behavior of Single-level Thoracic and Lumbar Fractures Treated With Pedicle Screw Fixation.

Abstract

This was a retrospective cohort study to objectively analyze the behavior of single-level thoracic (T), thoracolumbar (TL), and lumbar (L) fractures treated with posterior instrumentation alone and to understand which factors influence the ability to restore and maintain normal spinal alignment. Posterior screw fixation of dorsal and lumbar spine fractures allows fracture stabilization, correction of kyphotic deformity and restoration of vertebral height. The load-sharing classification identifies fractures that may need anterior instrumentation. Patients submitted to pedicle screw fixation of single-level T, TL, and L fractures were retrospectively analyzed. Data on patient demographics, neurological injury [American Spinal Injury Association (ASIA) score], and comorbidities were collected. Fractures were classified according to their anatomic region (T, TL, or L) and using the AO Spine and the load-sharing classifications. Local kyphosis angle, Cobb angle (CA), and changes in anterior vertebral height (AVH) were measured, to quantify intraoperative correction and loss of correction at 6 weeks and at last follow-up. A multivariate analysis was performed to identify the factors influencing the intraoperative correction and the loss of correction over time. From a total of 230 fractures, 115 patients with a mean age of 51.48 years were included. Pedicle screw fixation achieved a significant intraoperative correction of the CA, local kyphosis angle, and AVH. This correction was partially lost over time, but, at last follow-up, radiographic parameters were still significantly better than preoperatively. A regression model identified that age and body mass index influenced the correction of CA; ASIA classification influenced the correction of AVH. Posterior screw fixation allows for the restoration of spinal alignment, but this correction is less effective in elderly people and in patients with higher body mass index and higher degree of neurological injury.Level of Study: Level III.